Hi Gingergeezer, ... great handle BTW.
Here are a few things that I would try:
Definitely check out Doc'a troubleshooting video.
Might also want to have a look at Doc's
Yearly Maintenance video
Basically, make sure all jacks, sockets, & pots are clean and well grounded.
Sometimes brand new tubes are bad.
If you can, try tubes that you know are quiet in other amps.
Does it buzz without the foot switch plugged in ?
Is this an "export" Maz 8 or a US version ?
Head or studio combo ?
What are your settings ?
Do you play it with any knobs dimed?
Have you checked off all the usual suspects, ie:
Plugged into a well grounded power circuit.
No overhead lights on, especially fluorescents.
No cell phone close to the amp.
Eliminating hum can be a PITA.
Basically you have to step through a process of elimination
until you find the problem. Change one thing at a time,
and try the amp.
A bit of hum is normal in a single ended amp.
But there are ways to minimize it.
Excessive hum can probably be helped.
Good luck. Keep us posted.